A large number of methods for producing fuel-air mixtures for reciprocating internal combustion engines, such as Otto cycle engines, Diesel engines, 2-stroke engines, Wankel-type engines and any other compression-type engine are well known, and many are patented. However, as far as Applicant is aware, many previously disclosed methods, except Diesel and jet engines, attempt to produce a fuel vapor mixed thoroughly with air. In many of these methods, fuel is heated, in some instances to near a boiling point of the fuel, in order to convert the fuel to a gas prior to its induction into a combustion chamber. Virtually all attempt to minimize fuel droplet production and maximize fuel vapor production based on the belief that fuel droplets in the fuel/air mixture cause inefficient combustion, and generate more pollutants in the exhaust. In most engines, fuel spray from a carburator or fuel injector is simply sprayed into an intake manifold of the engine.
In gasoline engines, one major drawback to providing a stochiemetric fuel/air mixture wherein the fuel is in a vapor form is that the vapor provides a readily explosive mixture. This becomes a problem when loading on an engine causes pressures in the combustion chambers sufficient to raise a temperature of the fuel/air mixture to or beyond its flash point. This in turn causes the fuel/air mixture to explode all at once (rather than burning evenly in an outward direction from the spark plug), a condition commonly known as “ping”, or in older, worn engines “knock”, due to the knocking noise created as bearings of the piston connecting rods are slammed against the crankshaft under the force of the explosion. As might be imagined, such a condition is deleterious to bearings and other parts of the engine, and can greatly shorten engine life. For purposes of this application, both ping and knock are used to refer to a detonation of the fuel vapor/air mixture in a manner similar to an explosion rather than a controlled burn.
Where gasoline is simply sprayed into an engine manifold, as from a carburetor or fuel injector, droplets of all sizes enter the combustion chamber. Here, Applicant has discovered that fuel droplets larger than about 50 microns or so do not burn completely, creating unburned hydrocarbon pollutants. With respect to Diesel and jet fuel, incomplete burning also produces carbon particulate pollution in addition to gaseous hydrocarbon pollution.
In accordance with the present invention wherein a fog of size-limited fuel droplets of about 50 microns and less predominantly make up the fuel component of the fuel/air mixture, apparatus is provided that processes metered quantities of fuel delivered by a fuel injector, fuel valve (or other nozzle) or any other fuel metering device into an aerosol fog having droplets less than 50 microns in diameter and with a minimum of vapor. As stated, the object of this invention is to cause internal combustion engines such as Otto-cycle engines, Diesel engines, two-stroke engines, Wankel-type engines and other, such engines that compress an air/fuel mixture to operate more efficiently, with less pollution and without knock than has heretofore been possible. It has been discovered that fuel droplets of about 50 microns and less in diameter burn at a slower rate than a fuel vapor/air mixture that explodes, but significantly faster than the larger liquid fuel droplets delivered by conventional fuel delivery systems currently in use. In addition, it has been found that these smaller fuel droplets, when thoroughly mixed with air, burn more stoichiometrically than larger fuel droplets. It is believed a larger fuel droplet depletes the surrounding microenvironment of oxygen before burning completely, thus creating the unburned hydrocarbon pollutants found in exhaust gases. In contrast, fuel droplets smaller than about 50 microns in diameter consume surrounding oxygen in a stoichiometric relation when burned because of their extremely small size, thus the net fuel/air charge in a combustion chamber is burned completely, rapidly and with little to no hydrocarbon pollutants. It is also believed that since, in one embodiment of the instant invention, fuel is initially sprayed into a generally confined tube (designated as a STAR TUBE™ for purposes of this application) containing turbulence-inducing devices, vapor saturation of air within the tube prevents further evaporation of the fuel droplets, causing the fuel droplets to be reduced in size mechanically rather than by evaporation as the fuel droplets travel through the tube. Here, as the fuel, and particularly with respect to gasoline and other volatile fuels, is released from pressure of the fuel rail and exposed to the partial vacuum created by the downward travel of a nearby piston via the open intake valve, lighter, more volatile components of the fuel instantly evaporate and increase hydrocarbon vapor pressure within the tube, suppressing further evaporation of the fuel droplets. In addition, cooling due to rapid expansion of the evaporating lighter components of the fuel cools and stabilizes the fuel droplets within the closed environment within the STAR TUBE™. The fuel is then processed mechanically by turbulence-inducing devices in the STAR TUBE™ until the droplets reach a size sufficiently small so as to travel with a localized region of fuel-saturated air to the combustion chamber. The fuel/air mixture is thoroughly mixed as it passes the intake valve and compressed in the combustion chamber, causing a rapid, even burning of the fuel.
In addition to the foregoing, it is also well known that when a cold engine is started, only about ⅕ of the fuel is burned. Only after the engine warms does it become possible to burn the fuel stoichiometrically. During the warm-up period, the quantity of unburned hydrocarbon pollutants produced by the engine are much greater than in a warm engine. Applicant's system for fuel processing also greatly reduces such pollutants developed by a cold engine by providing an air/fuel mixture that burns readily and completely.
Engines such as Diesel or other direct injection engines may also benefit from fuel processed into droplets sized 50 microns and less. Here, an aerosol fog of Diesel fuel having droplets of 50 microns and less will burn faster and ignite easier than a fuel spray of larger droplets, this fuel fog increasing efficiency and reducing unburned hydrocarbon pollutants and particulates in the exhaust of Diesel-type engines. Also, such combustion properties allow a more stoichiometric proportion of Diesel fuel/air to be used. Similarly, turbine and other jet engines, which typically are sources of unburned hydrocarbon pollution and particulates because of poor fuel management, particularly in afterburner modes of operation, may also benefit by fuel provided as a fog of droplets sized 50 microns and less. These droplets burn faster and/are ignited easier than would otherwise be the case. This allows more of a stoichiometric combustion of the jet fuel, reduces particulates and hydrocarbon pollutants in the exhaust gas, increases the efficiency the engine and may even prolong life of a jet engine.
In accordance with the foregoing, it is one object of the invention to provide a fuel delivery system that processes fuel into a fuel fog having fuel droplets of a maximum predetermined size. It is another object of the invention to provide apparatus for generating a fuel/air mixture wherein the fuel is incorporated into a fog of droplets sized 50 microns and less to as great an extent as possible, with as little vapor as possible. It is yet another object of the invention to provide a closed STAR TUBE™ and fuel injector or other fuel nozzle as a single integral unit or assembly sized so as to be as direct a replacement as possible for a conventional fuel injector. Other objects of the invention will become apparent upon a reading of the following appended specification.